Climbing Stairs

1public int climbStairs(int n) {
2    if (n <= 1) {
3        return 1;
4    }
5
6    int[] dp = new int[n + 1];
7    dp[0] = 1;
8    dp[1] = 1;
9
10    for (int i = 2; i <= n; i++) {
11        dp[i] = dp[i - 1] + dp[i - 2];
12    }
13
14    return dp[n];
15}